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  <xs:element id="nix_MassachusettsBusinessDomain" abstract="true" name="MassachusettsBusinessDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NIPSCOHoldingsIIMember" abstract="true" name="NIPSCOHoldingsIIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_BasisOfAccountingPresentationLineItems" abstract="true" name="BasisOfAccountingPresentationLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_NumberOfCustomers" abstract="false" name="NumberOfCustomers" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="nix_PreTaxRateForAllowanceForFundsUsedDuringConstruction" abstract="false" name="PreTaxRateForAllowanceForFundsUsedDuringConstruction" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_RecentlyAdoptedAccountingPronouncementsAbstract" abstract="true" name="RecentlyAdoptedAccountingPronouncementsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_RecentlyAdoptedAccountingPronouncementsTable" abstract="true" name="RecentlyAdoptedAccountingPronouncementsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_RecentlyAdoptedAccountingPronouncementsLineItems" abstract="true" name="RecentlyAdoptedAccountingPronouncementsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_ServiceAreaByCounty" abstract="false" name="ServiceAreaByCounty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="nix_ResidentialMember" abstract="true" name="ResidentialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_CommercialMember" abstract="true" name="CommercialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_IndustrialMember" abstract="true" name="IndustrialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_OffsystemMember" abstract="true" name="OffsystemMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_Misc.Member" abstract="true" name="Misc.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_WholesaleMember" abstract="true" name="WholesaleMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_PublicAuthorityMember" abstract="true" name="PublicAuthorityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_GasDistributionOperationsMember" abstract="true" name="GasDistributionOperationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ElectricOperationsMember" abstract="true" name="ElectricOperationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NIPSCOOperationsMember" abstract="true" name="NIPSCOOperationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_ColumbiaOperationsMember" abstract="true" name="ColumbiaOperationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_NIPSCOElectricGenerationMember" abstract="true" name="NIPSCOElectricGenerationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_NiSourceElectricGenerationAndPowerDeliveryMember" abstract="true" name="NiSourceElectricGenerationAndPowerDeliveryMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_NIPSCOGasDistributionMember" abstract="true" name="NIPSCOGasDistributionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_NiSourceGasDistributionMember" abstract="true" name="NiSourceGasDistributionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_CustomerAccountsReceivableBilledLessReserve" abstract="false" name="CustomerAccountsReceivableBilledLessReserve" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_CustomerAccountsReceivableUnbilledLessReserve" abstract="false" name="CustomerAccountsReceivableUnbilledLessReserve" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_AllowanceForCreditLossesAbstract" abstract="true" name="AllowanceForCreditLossesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_IndianaCrossroadsWindMember" abstract="true" name="IndianaCrossroadsWindMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_IndianaCrossroadsSolarMember" abstract="true" name="IndianaCrossroadsSolarMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_DunnsBridgeIMember" abstract="true" name="DunnsBridgeIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_NiSourceMember" abstract="true" name="NiSourceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_WindPowerPurchaseAgreementPurchasePercentage" abstract="false" name="WindPowerPurchaseAgreementPurchasePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_NameplateCapacity" abstract="false" name="NameplateCapacity" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:powerItemType"/>
  <xs:element id="nix_ObligationToTheDeveloper" abstract="false" name="ObligationToTheDeveloper" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaidToDeveloper" abstract="false" name="InterestPaidToDeveloper" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_NIPSCOsCashContribution" abstract="false" name="NIPSCOsCashContribution" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_IncomeAttributableToNoncontrollingTable" abstract="true" name="IncomeAttributableToNoncontrollingTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_IncomeAttributableToNoncontrollingLineItems" abstract="true" name="IncomeAttributableToNoncontrollingLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_CashContributionsNoncontrollingInterestTable" abstract="true" name="CashContributionsNoncontrollingInterestTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_CashContributionsNoncontrollingInterestLineItems" abstract="true" name="CashContributionsNoncontrollingInterestLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_TaxEquityPartnersCashContribution" abstract="false" name="TaxEquityPartnersCashContribution" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalCashContributions" abstract="false" name="TotalCashContributions" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ScheduleOfVIEAssetsAndLiabilitiesTable" abstract="true" name="ScheduleOfVIEAssetsAndLiabilitiesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_VIEAssetsAndLiabilitiesLineItems" abstract="true" name="VIEAssetsAndLiabilitiesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_EarningsPerShareTable" abstract="true" name="EarningsPerShareTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_EquityUnitsMember" abstract="true" name="EquityUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_EarningsPerShareLineItems" abstract="true" name="EarningsPerShareLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseAgreementsIfConverted" abstract="false" name="IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseAgreementsIfConverted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="nix_ForwardFebruary21Member" abstract="true" name="ForwardFebruary21Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ForwardJune2021Member" abstract="true" name="ForwardJune2021Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ForwardAugust2021Member" abstract="true" name="ForwardAugust2021Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_AtTheMarketProgramMember" abstract="true" name="AtTheMarketProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ForwardNovember2022Member" abstract="true" name="ForwardNovember2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ForwardFebruary23Member" abstract="true" name="ForwardFebruary23Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_ForwardMay22Member" abstract="true" name="ForwardMay22Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_ForwardSeptember27Member" abstract="true" name="ForwardSeptember27Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_ForwardSeptember30Member" abstract="true" name="ForwardSeptember30Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_ProceedsAxis" abstract="true" name="ProceedsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_ProceedsDomain" abstract="true" name="ProceedsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_GrossProceedsMember" abstract="true" name="GrossProceedsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NetProceedsMember" abstract="true" name="NetProceedsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_SeriesB1PreferredStockMember" abstract="true" name="SeriesB1PreferredStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_SeriesACorporateUnitsMember" abstract="true" name="SeriesACorporateUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_CommonStockAggregateSalePrice" abstract="false" name="CommonStockAggregateSalePrice" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PreferredStockDividendRateInitialMargin" abstract="false" name="PreferredStockDividendRateInitialMargin" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_PreferredStockDividendRateInitialMarginPlus1.000" abstract="false" name="PreferredStockDividendRateInitialMarginPlus1.000" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_PreferredStockDepositarySharesIssued" abstract="false" name="PreferredStockDepositarySharesIssued" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="nix_DepositaryStockLiquidationPreference" abstract="false" name="DepositaryStockLiquidationPreference" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="nix_NetProcessFromSale" abstract="false" name="NetProcessFromSale" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_UndividedBeneficialOwnershipInterestPercent" abstract="false" name="UndividedBeneficialOwnershipInterestPercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_CorporateUnitsContractAnnualRate" abstract="false" name="CorporateUnitsContractAnnualRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_SharesToBeIssuedUnderStockPurchaseContracts" abstract="false" name="SharesToBeIssuedUnderStockPurchaseContracts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="nix_EquityUnitsStockPurchaseContractLiabilityPayment" abstract="false" name="EquityUnitsStockPurchaseContractLiabilityPayment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PurchaseContractLiability" abstract="false" name="PurchaseContractLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseContractPaymentBalance" abstract="false" name="IncrementalCommonSharesAttributableToDilutiveEffectOfEquityUnitPurchaseContractPaymentBalance" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="nix_PreferredStockSharesRedeemed" abstract="false" name="PreferredStockSharesRedeemed" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="nix_ATMProgramEquityRemainingAvailableforIssuance" abstract="false" name="ATMProgramEquityRemainingAvailableforIssuance" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EquityUnitsAbstract" abstract="true" name="EquityUnitsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_EquityUnitsTable" abstract="true" name="EquityUnitsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_EquityUnitsCompenentsAxis" abstract="true" name="EquityUnitsCompenentsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_EquityUnitsCompenentsDomain" abstract="true" name="EquityUnitsCompenentsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_PurchaseContractLiabilityMember" abstract="true" name="PurchaseContractLiabilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_EquityUnitsLineItems" abstract="true" name="EquityUnitsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_AccountsReceivableProgramMember" abstract="true" name="AccountsReceivableProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_SeasonalLimit" abstract="false" name="SeasonalLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_CashFromFinancingActivitiesRelatedToChangeInShortTermBorrowingsDueToSecuritizationTransactions" abstract="false" name="CashFromFinancingActivitiesRelatedToChangeInShortTermBorrowingsDueToSecuritizationTransactions" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_SecuritizationTransactionFees" abstract="false" name="SecuritizationTransactionFees" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_SecondTermCreditAgreement" abstract="false" name="SecondTermCreditAgreement" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_SecondTCADebtInterestRate" abstract="false" name="SecondTCADebtInterestRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="nix_A3.60NotesDue2030Member" abstract="true" name="A3.60NotesDue2030Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A095NotesDue2025Member" abstract="true" name="A095NotesDue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A170NotesDue2031Member" abstract="true" name="A170NotesDue2031Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A095NotesDue2025And170NotesDue2031Member" abstract="true" name="A095NotesDue2025And170NotesDue2031Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A3.65NotesDue2023Member" abstract="true" name="A3.65NotesDue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A4.45NotesDue2021Member" abstract="true" name="A4.45NotesDue2021Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A2.65NotesDue2022Member" abstract="true" name="A2.65NotesDue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A3.85NotesDue2023Member" abstract="true" name="A3.85NotesDue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A6.25NotesDue2040Member" abstract="true" name="A6.25NotesDue2040Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A5.95NotesDue2041Member" abstract="true" name="A5.95NotesDue2041Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A5.89NotesDue2025Member" abstract="true" name="A5.89NotesDue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_SeniorNoteRedeemedAugustSeptember2020Member" abstract="true" name="SeniorNoteRedeemedAugustSeptember2020Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NoteRedeemedSeptember2020Member" abstract="true" name="NoteRedeemedSeptember2020Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A626NotesDue2028Member" abstract="true" name="A626NotesDue2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NiSourceCorporateServicesMember" abstract="true" name="NiSourceCorporateServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NIPSCOMember" abstract="true" name="NIPSCOMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A5.35NotesDue2034Member" abstract="true" name="A5.35NotesDue2034Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_A6.95NotesDue2054Member" abstract="true" name="A6.95NotesDue2054Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_A5.20NotesDue2029Member" abstract="true" name="A5.20NotesDue2029Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_A6.375NotesDue2054Member" abstract="true" name="A6.375NotesDue2054Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_DebtInstrumentTendered" abstract="false" name="DebtInstrumentTendered" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_WorkingCapitalAdjustment" abstract="false" name="WorkingCapitalAdjustment" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="nix_AssetSaleCovenantPercentageOfConsolidatedTotalAssets" abstract="false" name="AssetSaleCovenantPercentageOfConsolidatedTotalAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
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  <xs:element id="nix_AnnualRevenueIncreaseFromJointStipulationAndProposedSettlements" abstract="false" name="AnnualRevenueIncreaseFromJointStipulationAndProposedSettlements" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="nix_DerivativeGainStatementOfIncomeOrComprehensiveExtensibleEnumerationNotDisclosedFlag" abstract="false" name="DerivativeGainStatementOfIncomeOrComprehensiveExtensibleEnumerationNotDisclosedFlag" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="nix_CommodityPriceRiskProgramsMember" abstract="true" name="CommodityPriceRiskProgramsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
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  <xs:element id="nix_StateLossesNetOfFederalBenefitMember" abstract="true" name="StateLossesNetOfFederalBenefitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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  <xs:element id="nix_IncreaseDecreaseinEffectiveTaxRate" abstract="false" name="IncreaseDecreaseinEffectiveTaxRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_EffectiveIncomeTaxRateReconciliationTaxAccrualAdjustmentsPercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationTaxAccrualAdjustmentsPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_EffectiveIncomeTaxRateReconciliationTaxAccrualAdjustmentsAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationTaxAccrualAdjustmentsAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_IncreaseDecreaseInTaxExpense" abstract="false" name="IncreaseDecreaseInTaxExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DecreaseInAmortizationOfRegulatoryLiabilities" abstract="false" name="DecreaseInAmortizationOfRegulatoryLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="nix_OperatingLossCarryforwardAndInvestmentCreditsMember" abstract="true" name="OperatingLossCarryforwardAndInvestmentCreditsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_UtilizationExpenseOfOperatingLossCarryforwardsMember" abstract="true" name="UtilizationExpenseOfOperatingLossCarryforwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_ScheduleOfIncomeTaxExpenseBenefitLineItems" abstract="true" name="ScheduleOfIncomeTaxExpenseBenefitLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_ScheduleOfReasonsBehindDifferencesInComputationOfTotalIncomeTaxesTable" abstract="true" name="ScheduleOfReasonsBehindDifferencesInComputationOfTotalIncomeTaxesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_ReasonsBehindDifferencesInComputationOfTotalIncomeTaxesAxis" abstract="true" name="ReasonsBehindDifferencesInComputationOfTotalIncomeTaxesAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_ReasonsBehindDifferencesInComputationOfTotalIncomeTaxesDomain" abstract="true" name="ReasonsBehindDifferencesInComputationOfTotalIncomeTaxesDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ScheduleOfReasonsBehindDifferencesInComputationOfTotalIncomeTaxesLineItems" abstract="true" name="ScheduleOfReasonsBehindDifferencesInComputationOfTotalIncomeTaxesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_IncreasesreductionsintaxesresultingfromAbstract" abstract="true" name="IncreasesreductionsintaxesresultingfromAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_ScheduleOfPrincipalComponentsOfNetTaxExpenseTable" abstract="true" name="ScheduleOfPrincipalComponentsOfNetTaxExpenseTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_ScheduleOfPrincipalComponentsOfNetTaxExpenseAxis" abstract="true" name="ScheduleOfPrincipalComponentsOfNetTaxExpenseAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_ScheduleOfPrincipalComponentsOfNetTaxExpenseDomain" abstract="true" name="ScheduleOfPrincipalComponentsOfNetTaxExpenseDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ScheduleOfPrincipalComponentsOfNetTaxExpenseLineItems" abstract="true" name="ScheduleOfPrincipalComponentsOfNetTaxExpenseLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_AcceleratedDepreciationAndOtherPropertyDifferences" abstract="false" name="AcceleratedDepreciationAndOtherPropertyDifferences" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PartnershipBasisDifferences" abstract="false" name="PartnershipBasisDifferences" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherRegulatoryAssets" abstract="false" name="OtherRegulatoryAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DeferredInvestmentTaxCreditsAndOtherRegulatoryLiabilities" abstract="false" name="DeferredInvestmentTaxCreditsAndOtherRegulatoryLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DeferredTaxAssetsOtherAccruedLiabilitiesEnvironmental" abstract="false" name="DeferredTaxAssetsOtherAccruedLiabilitiesEnvironmental" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_UnrecognizedTaxBenefitsNetofRefundsandNetOperatingLossCarryforwards" abstract="false" name="UnrecognizedTaxBenefitsNetofRefundsandNetOperatingLossCarryforwards" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_CommingledFundsMember" abstract="true" name="CommingledFundsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ShortTermMoneyMarketsMember" abstract="true" name="ShortTermMoneyMarketsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_UnitedStatesEquitiesMember" abstract="true" name="UnitedStatesEquitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_InternationalEquitiesMember" abstract="true" name="InternationalEquitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_DomesticEquitiesMember" abstract="true" name="DomesticEquitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_RealEstateAndPrivateEquityAndHedgeFundsMember" abstract="true" name="RealEstateAndPrivateEquityAndHedgeFundsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_PrivateEquityMember" abstract="true" name="PrivateEquityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_PensionandOtherPostretirementBenefitsAbstract" abstract="true" name="PensionandOtherPostretirementBenefitsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_DefinedBenefitPlanTargetAllocationPercentageOfTotalAssets" abstract="false" name="DefinedBenefitPlanTargetAllocationPercentageOfTotalAssets" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_PrivateEquityLimitedPartnershipsMember" abstract="true" name="PrivateEquityLimitedPartnershipsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_MutualFundsMember" abstract="true" name="MutualFundsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_UnitedStatesMultiStrategyMember" abstract="true" name="UnitedStatesMultiStrategyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_InternationalMultiStrategyMember" abstract="true" name="InternationalMultiStrategyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_DistressedOpportunitiesMember" abstract="true" name="DistressedOpportunitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_DueToBrokersNetMember" abstract="true" name="DueToBrokersNetMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_AccruedInvestmentIncomeDividendsMember" abstract="true" name="AccruedInvestmentIncomeDividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ReceivablesPayablesMember" abstract="true" name="ReceivablesPayablesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_MortgagesAssetBackedSecuritiesMember" abstract="true" name="MortgagesAssetBackedSecuritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_OtherFixedIncomeMember" abstract="true" name="OtherFixedIncomeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_DefinedBenefitPlanFairValueOfPlanAssetsBeforePendingItems" abstract="false" name="DefinedBenefitPlanFairValueOfPlanAssetsBeforePendingItems" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PrivateEquityAndRealEstateLimitedPartnershipsMember" abstract="true" name="PrivateEquityAndRealEstateLimitedPartnershipsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NetAssetValueExcludedFromFairValueByInput" abstract="false" name="NetAssetValueExcludedFromFairValueByInput" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DefinedBenefitPlanEstimatedBenefitsPaidByIncurredSubsidy" abstract="false" name="DefinedBenefitPlanEstimatedBenefitsPaidByIncurredSubsidy" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_Definedbenefitplanrecognizedinaccumulatedothercomprehensiveincomenetgainsorlossesbeforeincometaxorregulatoryassetsorliabilities" abstract="false" name="Definedbenefitplanrecognizedinaccumulatedothercomprehensiveincomenetgainsorlossesbeforeincometaxorregulatoryassetsorliabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DefinedBenefitPlanAssumptionsUsedInCalculatingNetPeriodicCostDiscountRateforInterestCost" abstract="false" name="DefinedBenefitPlanAssumptionsUsedInCalculatingNetPeriodicCostDiscountRateforInterestCost" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeOrRegulatoryAssetOrLiability" abstract="false" name="DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeOrRegulatoryAssetOrLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_A2019AwardMember" abstract="true" name="A2019AwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A2020AwardMember" abstract="true" name="A2020AwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A2021AwardMember" abstract="true" name="A2021AwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A2021SpecialAwardMember" abstract="true" name="A2021SpecialAwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_FinancialMeasurementAxis" abstract="true" name="FinancialMeasurementAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_FinancialMeasurementDomain" abstract="true" name="FinancialMeasurementDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_NOEPSMember" abstract="true" name="NOEPSMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_CVIMember" abstract="true" name="CVIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_RTSRModifier" abstract="false" name="RTSRModifier" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="nix_ExcessTaxExpenseShareBasedCompensation" abstract="false" name="ExcessTaxExpenseShareBasedCompensation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PerformanceShareDetailsTable" abstract="true" name="PerformanceShareDetailsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_RelativeTotalShareholderReturnMember" abstract="true" name="RelativeTotalShareholderReturnMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A2022AwardMember" abstract="true" name="A2022AwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_A2023AwardMember" abstract="true" name="A2023AwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_A2024AwardMember" abstract="true" name="A2024AwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_PerformanceShareDetailsLineItems" abstract="true" name="PerformanceShareDetailsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_LeaseTypeAxis" abstract="true" name="LeaseTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_LeaseTypeDomain" abstract="true" name="LeaseTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_FleetLeaseMember" abstract="true" name="FleetLeaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_OfficeMember" abstract="true" name="OfficeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_RemainingLeaseTerm" abstract="false" name="RemainingLeaseTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="nix_LesseeLeaseRenewalTerm" abstract="false" name="LesseeLeaseRenewalTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="nix_FinanceLeaseCostTotal" abstract="false" name="FinanceLeaseCostTotal" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_Totalleasedassets" abstract="false" name="Totalleasedassets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalLeaseLiability" abstract="false" name="TotalLeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LeaseMaturityTable" abstract="true" name="LeaseMaturityTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_LeaseMaturityLineItems" abstract="true" name="LeaseMaturityLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDueNextTwelveMonths" abstract="false" name="TotalFutureMinimumLeasePaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDueinTwoYears" abstract="false" name="TotalFutureMinimumLeasePaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDueinThreeYears" abstract="false" name="TotalFutureMinimumLeasePaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDueinFourYears" abstract="false" name="TotalFutureMinimumLeasePaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDueinFiveYears" abstract="false" name="TotalFutureMinimumLeasePaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDueThereafter" abstract="false" name="TotalFutureMinimumLeasePaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureMinimumLeasePaymentsDue" abstract="false" name="TotalFutureMinimumLeasePaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_UndiscountedExcessAmount" abstract="false" name="UndiscountedExcessAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ShorttermLeaseLiability" abstract="false" name="ShorttermLeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermLeaseLiability" abstract="false" name="LongtermLeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PurchaseAndServiceObligationsAxis" abstract="true" name="PurchaseAndServiceObligationsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_PurchaseAndServiceObligationsDomain" abstract="true" name="PurchaseAndServiceObligationsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_CoalTransportationMember" abstract="true" name="CoalTransportationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_PipelineServiceAgreementsMember" abstract="true" name="PipelineServiceAgreementsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ITServiceAgreementsMember" abstract="true" name="ITServiceAgreementsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_MgpSitesMember" abstract="true" name="MgpSitesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_LindeInc.Member" abstract="true" name="LindeInc.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_OtherCommitmentsAndContingenciesLineItems" abstract="true" name="OtherCommitmentsAndContingenciesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_WindPowerPurchaseAgreementCapacity" abstract="false" name="WindPowerPurchaseAgreementCapacity" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:powerItemType"/>
  <xs:element id="nix_LongTermPurchaseCommitmentExpirationYear" abstract="false" name="LongTermPurchaseCommitmentExpirationYear" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:gYearItemType"/>
  <xs:element id="nix_MajorRailOperators" abstract="false" name="MajorRailOperators" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="nix_PipelineReplacementExpenses" abstract="false" name="PipelineReplacementExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_NumberOfWasteDisposalSitesIdentifiedByProgram" abstract="false" name="NumberOfWasteDisposalSitesIdentifiedByProgram" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="nix_LiabilityForEstimatedRemediationCosts" abstract="false" name="LiabilityForEstimatedRemediationCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ReasonablyPossibleRemediationCostsVarianceFromReserve" abstract="false" name="ReasonablyPossibleRemediationCostsVarianceFromReserve" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EstimatedMaximumDisgorgementExposure" abstract="false" name="EstimatedMaximumDisgorgementExposure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LiabilityEstimateForUnrecoverableCCRCosts" abstract="false" name="LiabilityEstimateForUnrecoverableCCRCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDue" abstract="false" name="LongtermDebtFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="LongtermDebtFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDueinTwoYears" abstract="false" name="LongtermDebtFutureMinimumPaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDueinThreeYears" abstract="false" name="LongtermDebtFutureMinimumPaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDueinFourYears" abstract="false" name="LongtermDebtFutureMinimumPaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDueinFiveYears" abstract="false" name="LongtermDebtFutureMinimumPaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_LongtermDebtFutureMinimumPaymentsDueThereafter" abstract="false" name="LongtermDebtFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDue" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinTwoYears" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinThreeYears" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinFourYears" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinFiveYears" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueThereafter" abstract="false" name="InterestPaymentsonLongtermDebtFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDue" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDueinTwoYears" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDueinThreeYears" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDueinFourYears" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDueinFiveYears" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_EnergyCommodityContractsFutureMinimumPaymentsDueThereafter" abstract="false" name="EnergyCommodityContractsFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDue" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinTwoYears" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinThreeYears" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinFourYears" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinFiveYears" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueThereafter" abstract="false" name="ServiceObligationsPipelineServiceObligationsFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDue" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinTwoYears" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinThreeYears" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinFourYears" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinFiveYears" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueThereafter" abstract="false" name="ServiceObligationsITServiceObligationsFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueThereafter" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInFiveYears" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInFourYears" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInThreeYears" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInTwoYears" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueInTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDue" abstract="false" name="PlantEquipmentPurchaseObligationsFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDue" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDueNextTwelveMonths" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDueinTwoYears" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDueinThreeYears" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDueinFourYears" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDueinFiveYears" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherLiabilitiesFutureMinimumPaymentsDueThereafter" abstract="false" name="OtherLiabilitiesFutureMinimumPaymentsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDue" abstract="false" name="TotalFutureContractualObligationsDue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDueNextTwelveMonths" abstract="false" name="TotalFutureContractualObligationsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDueinTwoYears" abstract="false" name="TotalFutureContractualObligationsDueinTwoYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDueinThreeYears" abstract="false" name="TotalFutureContractualObligationsDueinThreeYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDueinFourYears" abstract="false" name="TotalFutureContractualObligationsDueinFourYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDueinFiveYears" abstract="false" name="TotalFutureContractualObligationsDueinFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_TotalFutureContractualObligationsDueThereafter" abstract="false" name="TotalFutureContractualObligationsDueThereafter" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DisposalGroupNotDiscontinuedOperationsGainLossOnWriteDown" abstract="false" name="DisposalGroupNotDiscontinuedOperationsGainLossOnWriteDown" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_OtherNonoperatingIncomeTable" abstract="true" name="OtherNonoperatingIncomeTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_InterestRateSwapSettledMember" abstract="true" name="InterestRateSwapSettledMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_OtherNonoperatingIncomeLineItems" abstract="true" name="OtherNonoperatingIncomeLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_CharitableContributions" abstract="false" name="CharitableContributions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_PensionandOtherPostretirementNonServiceCost" abstract="false" name="PensionandOtherPostretirementNonServiceCost" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_SaleOfEmissionReductionCredits" abstract="false" name="SaleOfEmissionReductionCredits" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_MiscellaneousNonOperatingIncomeExpense" abstract="false" name="MiscellaneousNonOperatingIncomeExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_DiscountOnPrepaymentTransaction" abstract="false" name="DiscountOnPrepaymentTransaction" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_AllowanceForBorrowedFundsUsedAndInterestCapitalizedDuringConstruction" abstract="false" name="AllowanceForBorrowedFundsUsedAndInterestCapitalizedDuringConstruction" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_Debtbasedpostinservicecarryingcharges" abstract="false" name="Debtbasedpostinservicecarryingcharges" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_SupplementalCashflowTable" abstract="true" name="SupplementalCashflowTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_SupplementalCashflowAxis" abstract="true" name="SupplementalCashflowAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="nix_SupplementalcashflowDomain" abstract="true" name="SupplementalcashflowDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_SupplementalCashFlowLineItems" abstract="true" name="SupplementalCashFlowLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_NoncashtransactionsAbstract" abstract="true" name="NoncashtransactionsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_NoncashorPartNoncashAcquisitionFixedAssetsAcquiredOperatingLease" abstract="false" name="NoncashorPartNoncashAcquisitionFixedAssetsAcquiredOperatingLease" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ReclassificationofOtherPropertytoRegulatoryAssets" abstract="false" name="ReclassificationofOtherPropertytoRegulatoryAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="nix_ScheduleofinterestandincometaxespaidAbstract" abstract="true" name="ScheduleofinterestandincometaxespaidAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="nix_ReserveForAccountsReceivableMember" abstract="true" name="ReserveForAccountsReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ReserveForOtherInvestmentsMember" abstract="true" name="ReserveForOtherInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ReserveForDeferredChargesAndOtherMember" abstract="true" name="ReserveForDeferredChargesAndOtherMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="nix_ShawnAndersonMember" abstract="true" name="ShawnAndersonMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="nix_MichaelJesanisMember" abstract="true" name="MichaelJesanisMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
